The present disclosure relates to calibration fluids for rheometers and the related methods.
A drilling fluid or mud is a specially designed fluid that is circulated through a wellbore as the wellbore is being drilled to facilitate the drilling operation. The various functions of a drilling fluid include removing drill cuttings from the wellbore, cooling and lubricating the drill bit, aiding in support of the drill pipe and drill bit, and providing a hydrostatic head to maintain the integrity of the wellbore walls and prevent well blowouts. Specific drilling fluid systems are selected to optimize a drilling operation in accordance with the characteristics of a particular geological formation. For the drilling fluid to perform its functions, its optimum chemical and rheological properties must be controlled.
One property of the drilling fluid that is of interest is its rheology, and specific rheological properties may be desired for drilling and circulating the fluid through the wellbore. Generally, the drilling fluid should be sufficiently viscous to suspend drilled cuttings and other particulates and to carry the cuttings to the well surface. However, the drilling fluid should not be so viscous as to interfere with the drilling operation. To achieve such properties, drilling fluids are often complex fluids with several components like the base fluid, a weighting agent, a suspending agent, a viscosifier, and a fluid loss control agent.